This invention relates to indicator displays, and more particularly to a light-emitting diode display for a Universal-Serial-Bus (USB) flash-memory device.
Electronic storage drives often have indicator lamps. For example, a hard-disk drive on a personal computer (PC) may have a single light-emitting diode (LED) that is illuminated while the disk is being accessed. An external flash-memory peripheral drive may have an LED that is illuminated while being written. The user can safely remove the flash-memory drive or its media once the light goes out, indicating that the writing operation is completed.
Flash memory has gained wide acceptance for its non-volatile storage, which is ideal for portable devices that may lose power, since the data is not lost when stored in the flash memory. Flash memories are constructed from electrically-erasable programmable read-only memory (EEPROM) cells.
Universal-Serial-Bus (USB) has become a popular standard interface for connecting peripherals to a host such as a personal computer (PC). USB-based flash-memory storage devices or “drives” have been developed to transport data from one host to another, replacing floppy disks. While large external flash drives may be used, smaller USB flash drives known as key-chain or key drives have been a rapidly growing market.
A USB flash-memory device can be constructed from a microcontroller, a flash-memory controller or interface, and one or more flash-memory chips. A serial interface on the microcontroller connects to the USB bus to the host, and data from the serial interface is transferred through the microcontroller to the flash controller and is written to the flash-memory chips.
The microcontroller can drive an output port that connects externally to a LED. The microcontroller can then turn the LED on or off by writing a zero or a one to the output port. The microcontroller can set the output port to a one when activity is occurring on the drive, such as any access of the flash memory, such as read, write and erase.
While such an LED activity light is useful, the LED is often small and barely noticeable to the user. A more elaborate display is desired to better capture the user's attention. A display for a USB flash drive is desired that has multiple LED's. A more dazzling display on a USB flash drive is desirable that can noticeably tell the user when data is being transferred to and from the flash drive. A display that could also be a selling point for the USB flash drive is desired, since the dazzling display could be made to flash on the display model in a store.